Tuesday’s Illinois House primaries showcase a pair of veteran House incumbents in the fight for their political lives — a Republican against a freshman lawmaker nearly half his age, and a Democrat with a famous last name in a battle with a former congresswoman.

All eyes are on the generational face-off between Republican Rep. Donald Manzullo, a two-decade House veteran, and freshman Rep. Adam Kinzinger. Democratic Rep. Jesse Jackson Jr., meanwhile, is facing the most serious threat of his eight-term congressional career from former Democratic Rep. Debbie Halvorson.

Also on the ballot are two progressive favorites looking to upend Democratic Party-backed choices. And after helping to unseat Ohio Rep. Jean Schmidt, the Campaign for Primary Accountability — an anti-incumbent super PAC playing in congressional races — is trying to make two Illinois members the next casualties.

Here’s POLITICO’s five things to watch on Tuesday.

The kid vs. the veteran

The contest pits two pols of different eras, with the 67-year-old, 10-term Manzullo looking to fend off a freshman rival 33 years his junior.

Kinzinger scored big when he nabbed the backing of House Majority Leader Eric Cantor, who in endorsing the freshman praised him as “a new breed of conservative.” He also has the financial support of much of the 87-member House GOP freshman class.

Manzullo has the backing of longtime House veterans like former House speaker and Illinois Rep. Dennis Hastert and Wisconsin Rep. Tom Petri. But the veteran lawmaker also has the support of tea party groups like FreedomWorks and the Illinois Tea Party, many of which backed Kinzinger the last go-round.

Kinzinger has aggressively sought to advance the past-vs.-future narrative, running TV ads calling Manzullo “part of the old majority that lost its way on spending.” In another spot, Kinzinger said he came to Congress “with a new way of doing things.”

The Illinois race is the first of two member-vs.-member primary battles pitting an up-and-coming freshman Republican lawmaker against a grizzled veteran. The other, between first-term Florida Rep. Sandy Adams and House Transportation Committee Chairman John Mica, takes place in August.

Will retreads continue to struggle?

It hasn’t been an easy start to the campaign season for casualties of the 2010 cycle waging comeback bids. Former Democratic Rep. Mary Jo Kilroy fell short in the Ohio primary, and former GOP Rep. Parker Griffith was crushed in a bid to unseat Republican Rep. Mo Brooks in Alabama.

On Tuesday, two other 2010 castoffs, former Democratic Reps. Bill Foster and Halvorson, will face primary battles. Halvorson is the decided underdog in the race for a suburban Chicago-area seat against Jackson. Jackson’s campaign recently released an internal survey showing the congressman leading Halvorson by a gaping margin — numbers that her camp haven’t rebutted.

Jackson’s campaign is targeting Halvorson’s congressional career, releasing a hard-hitting radio ad accusing her of casting 88 votes against President Barack Obama’s agenda in an effort to brand her as too conservative for the district and out of touch with the Democratic Party.

Foster, who is looking to unseat veteran GOP Rep. Judy Biggert, is expected to win the Democratic nomination against several lesser-known opponents.

At the outset of the primary season, more than a half-dozen former members were looking to reclaim the seats they lost two years ago.

The Blago shadow

Halvorson has banked much of her primary campaign on highlighting the ethical troubles that have plagued Jackson in recent years — particularly his role in the controversy surrounding former Illinois Gov. Rod Blagojevich’s efforts to sell Obama’s Senate seat.

The House Ethics Committee is currently reviewing whether Jackson used federal dollars to wage a public campaign to persuade the then-governor to appoint him to serve the remainder of Obama’s Senate term. It has never been proven that Jackson did anything illegal in the Blagojevich case, and Jackson has denied any wrongdoing.

Last week, with Blagojevich heading to prison, Halvorson held a news conference to call on Robert Blagojevich, the former governor’s brother, to reveal what he knew about Jackson’s ultimately unsuccessful effort to win a Senate appointment. Halvorson also aired a radio ad in the waning days of the race saying that, “Junior’s too focused on his own problems to fix ours.”

The outcome of the race will shed light on whether Jackson has been damaged by his association with the scandal.

Progressives vs. the establishment

Two Democratic primaries will pit liberal favorites against foes who have won the support of the party hierarchy.

The most closely watched of these contests is in the Chicago suburbs, where Ilya Sheyman, a 25-year-old progressive activist and tax activist Brad Schneider are battling for the right to take on GOP Rep. Robert Dold.

Sheyman has captured the imagination of progressives nationwide, winning the backing of groups ranging from MoveOn.org to the Progressive Change Campaign Committee and liberals like former Vermont Gov. Howard Dean and former Wisconsin Sen. Russ Feingold. Schneider, meanwhile, has secured the financial backing of House Minority Whip Steny Hoyer and Pennsylvania Rep. Allyson Schwartz, who heads recruiting for the Democratic Congressional Campaign Committee.

In downstate Illinois, David Gill, who has won the support of the Progressive Democrats of America, is facing off against Greene County State’s Attorney Matt Goetten, who’s backed by a range of establishment figures including Sen. Dick Durbin. The winner of the primary will face off against longtime GOP Rep. Tim Johnson in November.

Sheyman and Gill have both blasted their respective foes as too moderate and weak-kneed in their support for liberal ideals.

Can CPA claim another scalp?

After helping to oust Schmidt, the Campaign for Primary Accountability had less success in Alabama. GOP Reps. Spencer Bachus and Jo Bonner, its two targets in the state, both won their primaries.

In Illinois, CPA is looking to defeat Manzullo and Jackson — entrenched officeholders who haven’t faced tough races in years. The group has spent heavily against Manzullo, dumping $210,000 in his race, much of it on TV ads blasting the 10-term lawmaker on spending. CPA has spent around $90,000 in Jackson’s contest.

Even though it fell short against Bachus and Bonner, those involved with the CPA are quick to argue that both incumbents had a far tougher time winning renomination than in previous years, with each held to less than 60 percent of the vote. In both races, the group provided assistance to badly underfunded challengers.

A win on Tuesday would provide momentum to the group’s efforts as it looks toward the April 24 primary in Pennsylvania, where it has signaled its interest in targeting GOP Rep. Tim Murphy and Democratic Rep. Tim Holden.